Work
carried out in laboratories at the two universities has revealed that graphene
can extract radioactive materials from water solutions with great efficiency.
This property can be harnessed to rid places of radiation contamination –
places like Fukushima, for example – or to improve technology for extracting
rare earth metals and shale hydrocarbons. The collaborative work was published
in the Physical Chemistry Chemical
Physics journal.

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During experiments, researchers found that microscopic
flakes of graphene oxide, with a thickness of just one layer of atoms, quickly
connect with radionuclides of various origins and collect their separate ions
in hard bodies. These flakes are easily dissolved in water, and once they have
absorbed the radioactive substances, they gather in clusters which are easy to
recover and even use – for example, they can be burned.

According to James Tour who leads the group from Rice
University, this discovery could be a real boon when cleaning up radioactive
contamination hotspots, like, for example, the area around the Fukushima No. 1
nuclear power plant.

Moreover, according to Tour, when applied, the discovery
could significantly lower the cost of fracking (a process currently used for
extracting shale oil and gas).

Graphene oxide is a wonderful substance that appeared soon
after grapheme. It was immediately clear that it had a number of very different
applications and uses, and graphene’s ability to remove radioactive toxins from
water so effectively came as no real surprise.

However, according Stepan Kalmykov, leader of the dosimetry
and environmental radioactivity lab at Moscow State University’s chemistry
department, everyone involved in the experiment was bowled over by just how
fast graphene was able to clean up radiation.

The atom-thick graphene oxide flakes were synthesized by
Tour’s group, and they were then tested in experiments conducted in Kalmykov’s
laboratory. The scientists tested the flakes in solutions containing uranium,
plutonium, as well as sodium and calcium, which prevent absorption.

Even with
controls designed to slow down the process, graphene oxide showed itself to be
much more effective and efficient than other absorbents traditionally used for
cleaning up radioactive materials – substances such as bentonite clays and
granular activated carbon, for example. Radioactive impurities were
precipitated in a matter of minutes.

According to Tour, the idea of using graphene oxide for
cleaning radioactive impurities (as well as the idea of holding joint
experiments to this end) first came about several years ago at a seminar, where
his doctoral student, Alexander Slesarev, happened to meet Anna Romanchuk, a
doctoral student from Kalmykov’s laboratory. With the exception of James Tour
himself, the article is authored solely by Russian scientists.

One of the main directions of this joint effort was to find
means of extracting radioactive actinide and lanthanide isotopes from
solutions. These 30 elements on the periodic table form the so-called
rare-earth element category. The presence of radioactive isotopes in their ores
and solutions means extracting them can pose a serious health risk.

In the
United States, for example, their extraction is practically banned, because it
does not conform to environmental standards. This is despite the fact that
rare-earth elements are in hot demand for the electronics industry and, in
particular, for supplying the world with an ever-increasing number of mobile
phones.

In China, these environmental standards are not so exacting; partially
thanks to this, China has been able to corner the rare metals market. Using
graphene to rid rare metals of radioactive toxins could very well weaken
China’s hold on the market.

As for fracking, much also centers on naturally formed
radionuclides, according to Tour. During this process, a pressurized mixture of
water, sand and a number of chemical substances are pumped into a horizontal
mine. The impact of this pressurized mixture makes cracks in the inner surface
of the shale layer. When the liquid is sucked out of the mine, the oil and gas
that have been freed from the rocks also start to trickle out.

This is a very
expensive procedure that entails some serious environmental consequences: one
such consequence has to do with the radionuclides that are brought up to the
surface along with the water and chemical solution. Thus, graphene oxide
can also come into its own here, helping to clean up radioactive contaminates
released in the process of fracking.